1. Field of the Invention
The invention relates to a process for the manufacture of organopolysiloxanes which are suitable as active ingredients of abhesive coating materials for two-dimensional carriers and especially for paper or plastic films. The process involves the reaction of organopolysiloxanes which have SiCl groups with pentaerythritol triacrylate or pentaerythritol trimethacrylate. Optionally, HCl-binding neutralizing agents can be added.
2. Description of the Prior Art
A process is described in German Offenlegungsschrift No. 2,747,233 for the manufacture of organopolysiloxanes which are modified with acrylic esters or methacrylic esters. In this process, methacrylic esters or methacrylic esters having COH groups are reacted with organopolysiloxanes which have SiX groups (X=alkoxyl, hydroxyl or chloro), optionally in the presence of catalysts. This process is characterized by the fact that the organopolysiloxanes are reacted with 0.05 to equimolar amounts, based on the COH and SiX groups, of pentaerythritol triacrylate or pentaerythritol trimethacrylate using conventional procedures.
The compounds prepared according to this German Offenlegungsschrift have the advantage that, after the addition of known initiators, such as, for example, benzophenone or benzoin ethers, they can be cured by UV radiation in a very short time and generally in less than one second. These compounds may, therefore, be used with particular advantage as bonding agents or as bonding agent additives for printing inks, the printing inks being fixed by UV curing on the carrier. At the same time, these cured printing inks are hydrophobic. The products of the process may also be used for coating paper, wood or metal surfaces. For example, it is possible to produce coating materials from these compounds, which endow the paper with a high degree of gloss. However, coating materials with abhesive properties which would permit the use of papers so coated as release papers, cannot be obtained by this process.